1. Mats Selen, HEP-2005 1 Measuring Strong Phases, Charm Mixing, and DCSD at CLEO-c Mats Selen, University of Illinois HEP 2005, July 22, Lisboa, Portugal

2. Mats Selen, HEP-2005 2 CLEO-II.V (9/fb) CLEO-III (14/fb) CLEO-c (281/pb) New RICH New Drift Chamber New silicon New Trigger & DAQ Replace silicon with a wire vertex chamber CLEO Evolution

3. Mats Selen, HEP-2005 3 CLEO-c & D Tagging Tag one D meson in a selected tag mode. Study decays of other D, (signal D) e + e -   (3770)  DD  Pure DD final state, no additional particles (E D = E beam ).  Low particle multiplicity ~ 5-6 charged particles/event  Good coverage to reconstruct in semileptonic decays  Pure J PC = 1  initial state Targeted Analyses  Mixing (x 2 +y 2 ):DD  (K - l +  , (K -  + ) 2  cos  :Double Tag Events: K -  + vs CP±  Charm Mixing (y): Flavor Tag vs CP±  DCS: Wrong sign decays K -  + vs K - l +  Comprehensive Analysis   Combined analysis to extract mixing parameters, DCS, strong phase plus charm hadronic branching fractions Analysis Preview Charm Mixing, DCS, and cos  impact naïve interpretation of branching fraction analysis extension of Phys.Lett.B508:37-43,2001 hep-ph/0103110 Gronau/Grossman/Rosner & hep-ph/0207165 Atwood/Petrov See Asner & Sun, CLNS 05/1923 e+e+ ee  ++ K+K+ 

4. Mats Selen, HEP-2005 4 Overview of fitting technique Independent of L and cross section Single tags D candidate mass (GeV) Double tags D candidate mass (GeV) Kinematics analogous to  (4S)  BB: identify D with  (M BC ) ~ 1.3 MeV, x2 with  0  (  E) ~ 7—10 MeV, x2 with  0 15120 ± 180 377 ± 20 56 pb -1 sample

5. Mats Selen, HEP-2005 5 (log scale)! 6 D + Modes 3 D 0 Modes 2484 ± 51 (combined) 1650 ± 42 (combined) Single tagsDouble tags Global fit pioneered by Mark III N DD & B i ’s extracted from single and double tag yields with  2 minimization technique. D 0 D + 56 pb -1 sample See Gao’s talk on CLEO hadronic branching fractions measurement.

6. Mats Selen, HEP-2005 6 It’s a feature, not a problem… The CLEO hadronic branching fraction analysis did not include CP specific final states since the quantum corrections to these are not consistent with the simple fitting approach used. If we take these effects into account properly we will learn more ! –That’s the point of this talk.

7. Mats Selen, HEP-2005 7 A simple way to understand what CP-tags can do for us: For the moment, ignore CP violation and mixing and write mass eigenstates D 1 and D 2 as Consider the amplitudes for these mass eigenstates decaying to     : A1A1 A2A2 i.e. the CP even & CP odd rates to a specific final state will not be the same ! In reality these are much shorter !

8. Mats Selen, HEP-2005 8 The rate for the CP even D 1 to decay to     is given by: where Similarly, the rate for the CP odd D 2 to decay to     is given by: And to first order in r the asymmetry between CP even and CP odd tagged      events is given by: Measuring rate differences yields information about  if we know r !!

9. Mats Selen, HEP-2005 9 If we do the math correctly (i.e. we don’t ignore mixing etc) then we find that the rates will depend on the mixing parameters x and y as well as on r and z. By simultaneously measuring a collection of various rates we might expect to have enough constraints that all of the above can be (over) determined. We consider flavor tagged final states f and f, CP tagged final states S + and S  And semileptonic final states l  and l . Reminder

10. Mats Selen, HEP-2005 10 What we learn from various Single and Double tag rates Where From DD threshold running From D  sD + s (DD  ) threshold running Biggest effects in CP ± 1 final states Big effect - show plots

11. Mats Selen, HEP-2005 11 KSKS K+KK+K Double tag yield for (K + K  ) vs (KSp0) = 40 events Naïve expectation ( L  B ) KK x ( L  B ) Ks  = 9.5 events We see the predicted factor of 4 from (CP-)(CP+) constructive interference

12. Mats Selen, HEP-2005 12 CP tags are clearly very important… CP+ D0D0 Note log scale

13. Mats Selen, HEP-2005 13 Even our dirtiest CP+ tag is not so bad…

14. Mats Selen, HEP-2005 14 Will use both 2 and 3-body CP- tags as well… Example: D 0  K S K + K  is mostly CP odd K S 

15. Mats Selen, HEP-2005 15 Its also very important to do well with semileptonic modes… Inclusive semileptonic decays versus K  tags. 281 pb -1

16. Mats Selen, HEP-2005 16 Explore the sensitivity of this method using Monte Carlo (The number of CP+ tags will limit the statistical precision) (Yield from 1 fb -1 )

17. Mats Selen, HEP-2005 17 (Yield from 1 fb -1 ) Better if world average value for r K  is used.

18. Mats Selen, HEP-2005 18 Combined QC analysis Summary In correlated D 0 D 0 system, use time- integrated single and double tag yields to probe mixing and DCS parameters “Targeted” analyses provide first measurement of cos  and improved limit on R M “Comprehensive” analysis -Simultaneous fit for hadronic and semileptonic branching fractions, mixing and DCS parameters Will be first direct measurement of cos(  ) Projections of CLEO-c Sensitivity